Multiple unchecked buffers exist in the POP3 and HTTP Proxy components of SapporoWorks WinProxy which could open up the possibilities of denial of service attacks or remote execution of arbitrary code.

Performing a "GET /" on port 8080 will cause WinProxy to stop responding.

The USER, PASS, LIST, RETR, and DELE commands allow for arbitrary code to be executed when strings over 312 bytes are entered. The USER and PASS command are vulnerable to buffer overflow even without authentication procedures.